Produced through an elastic scattering interaction with the atoms in the sample that results in the primary electron being re-emitted from the specimen. The electron is said to have backscattered (or reflected back) from the sample. In backscattering, the electron trajectory is changed by more than 90 deg from the forward direction of motion. This results in the scattered electron propagating back in the general direction of the original beam. Note that between the multiple elastic events (that form Backscattered electrons), the beam electrons may also be involved in inelastic events, and thus reduce the electron's energy. Backscattered electrons usually have energy in the kV range.

An electron microscope technique used for viewing crystallographic information based on backscattered electrons whose scattering efficiency depends on the crystallographic orientaiton of the specimen. See http://www.ebsd.com/

Upon irradiation of focused electron beam, electron-sensitive resists undergo chain-scission or crosslinking, resulting in solubility switch of materials during the subsequent development process (remove/retain exposed material in development depending on the tone of the resist).

Calcium carbonate (CaCO3)
Calcium carbonate (commonly found in chalk) is present in egg shells, snail shells, and the shells of many small marine organisms.
Practice scanning electron microscopy using a virtual SEM

The SEM uses a beam of high energy electrons generated by an electron gun, processed by magnetic lenses, focused at the specimen surface and systematically scanned (rastered) across the surface of a specimen.

A scanning electron microscope is a machine comprised of an electron generating component called the gun, a column through which the electron beam travels, a series of lenses to shape the electron beam, the sample chamber at the base, and a series of pumps to keep the system under vacuum.

The size (cross sectional diameter) that the cone of the beam makes on the surface of the sample affects 1) the resolution of the image and 2) the number of electrons generated (therefore the graininess of the image).

This type of machine is basically like a conventional SEM but has the advantage in low vacuum (LV) mode that the pressure can be adjusted in the sample chamber until the artefact of "electron charging" is removed from images.

The smallest distance we can see between points in a light microscope (LM) is about 200 nm [There are 1000000 nm (= nanometers) in 1 mm] whereas a typical scanning electron microscope (SEM) can distinguish gaps smaller than 10 nm.